Business Segment Information - Schedule Of Capital Expenditures (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Capital Expenditures	$ 26,705	$ 32,108	$ 24,229
Goodwill	504,853	408,063	390,300
A&D
Capital Expenditures	10,400	15,900	11,700
Goodwill	104,300	102,100	102,200
USG
Capital Expenditures	11,600	12,400	8,500
Goodwill	366,500	271,900	254,000
Test
Capital Expenditures	4,700	3,600	4,000
Goodwill	34,100	34,100	34,100
Corporate, Non-Segment [Member]
Capital Expenditures	$ 0	$ 200	$ 0